A vicinal diol has two hydroxyl groups on the same carbon atoms.
a. True
b. False
c. Ambiguous
d. None of the above

Hint: Vicinal positions are known as adjacent positions of a compound (means on adjacent atoms). And diols are alcohol groups (- OH).

Complete answer: We know that a diol is a chemical compound which contains two hydroxyl groups (−OH groups).
Some classes of diols:
Geminal diols: Geminal diols have two hydroxyl groups bonded to the same atom. These species arise by hydration of the carbonyl compounds. Below given is the example of geminal diols:



Vicinal diols: In a vicinal diol, the two hydroxyl groups occupy vicinal positions, they are attached to adjacent atoms. These compounds are called glycols. In a vicinal diol, the two hydroxyl groups occupy vicinal positions, that is, they are attached to adjacent atoms. These compounds are called glycols.
Diols such as ethylene glycol are used as co-monomer in polymerization reactions forming polymers. Below given is the structure of vicinal diol:
 

Some other diols are also there which have diols at 1,3 position, 1,4 position etc.
So, from the above explanation we can say that the given statement is ‘False’.